Scientists have found remarkable improvements in the lung health of children living in London’s Ultra Low Emissions Zone.
A landmark study of more than 3,400 primary school children found that those whose lung growth had been stunted by pollution showed significant improvements after the introduction of ULEZ in 2019 by Mayor Sadiq Khan.
Researchers said it was the strongest evidence yet that local clear air zones could help reduce some of the harm caused by pollution during childhood.
Young children are particularly susceptible to air pollution because their lungs and immune systems are still developing. This can leave them at risk of asthma, heart disease, diabetes and even premature death.
The study, carried out by scientists at Queen Mary University London and published in the Lancet Public Health journal, recruited six to nine-year-olds attending primary schools in London’s ultra low emission zone.
Over the course of five years, they had annual lung function and capacity tests, starting in the year before ULEZ was introduced and carrying on for four years after.
Their results were compared to children in Luton from similar backgrounds and with similar levels of physical activity.
At the start of the study, results showed children’s lungs in London were smaller in capacity than those in Luton, an area less polluted than the capital but that has a similar mix of pollutants.
But by the end, the children’s lung capacity reached near identical levels in both groups. The proportion of children in London with a “clinically impaired” lung capacity also fell from 14% to 9%.
Crucially, the results found that improve lung growth trajectories were strongly related to air quality improvements following the introduction of ULEZ.
Prof Chris Griffiths, a senior author on the study, told the BBC he was “absolutely stunned” when he first saw the results.
“The speed of catch up in lung capacity in the London group was surprising and impressive,” he said.
“This shows an ambitious clean air zone can drive pollution levels down, rapidly restoring children’s stunted lung growth.”
Reacting to the research, Sadiq Khan said it was proof “we were right to act and reinforces my decision to extend the benefits of cleaner air to every child in London”.
“Introducing and expanding ULEZ involved incredibly difficult decisions,” he added.
“It was very tough, and a vocal minority backed by vested interests made it extremely difficult, but I refused to stand by while air pollution continued to damage Londoners’ health.”